Fascinating storylines abound as the Dolphins open training camp Friday under the glare of HBO cameras and under pressure to reverse the fortunes of a franchise languishing in mediocrity for much of the past decade.

There’s Joe Philbin, the Dolphins’ sixth head coach (eight if you count interim coaches Jim Bates and Todd Bowles) since Don Shula retired.

There’s colorful receiver Chad Johnson attempting to revive his sputtering career.

There are new systems on both sides of the ball: a West Coast offense expected to make ample use of the no-huddle and a defense that will run out of a 4-3 base.

There’s the added element of the Dolphins being featured on HBO’s five-episode Hard Knocks reality series, debuting Aug. 7.

But the most absorbing subplot?

“I would have to say, as any Miami Dolphins fan would, that the quarterback position is the one that has the most intrigue at this point,” said offensive coordinator Mike Sherman, who will have significant input in a decision that will be made ultimately by Philbin.

Philbin said David Garrard and Matt Moore were “close” in performance throughout the offseason, and Ryan Tannehill will be given a chance to compete, though he faces longer odds than the two veteran quarterbacks.

Tannehill remained unsigned as of early Thursday evening, but the Dolphins were hopeful of completing a deal in the next day or two.

“I would hope after two or three weeks of camp, after that first preseason game, we’ll have a good feel of who [the starter] is going to be, and start getting him the reps he needs in order to take us into the season,” Sherman said.

Receiver Legedu Naanee said: “It’s better to know [the starting quarterback] from day one, obviously. The offense we run has a lot of timing, a lot of precision. The checks made are made by all the quarterbacks the same way.

“It could help us, if we ever have an injury situation. But obviously, you want to know sooner than later.”

Gut instinct

Philbin said he won’t rely on sheer numbers to pick a starter: “I’m not a huge stats guy,” he said. “I think I’m more of a guy that coaches on instinct and what your gut tells you, what your eyes tell you.”

Philbin said Garrard “still throws the ball with a lot of velocity and his accuracy has been good. Matt Moore has a good feel for the game. I like the way he’s caught onto the system.”

And of Tannehill, Philbin said, “It’s not fair to Ryan to say, ‘You’re not going to be ready this year.’ And then — one injury if he’s the No. 2, or two injuries if he’s the No. 3 — occur, and he’s starting, what are you going to tell him then?”

Steinbach signs

Concerned about their situation at right guard, the Dolphins on Thursday signed veteran lineman Eric Steinbach, who sat out last season after back surgery. An associate said Steinbach is healthy but might need time to get the rust off.

If he returns to his old form, Steinbach, 32, has a good chance to start ahead of Artis Hicks and John Jerry at right guard. He also can play tackle and center.

A former second-round pick out of Iowa (where he was coached by Philbin), Steinbach spent four years with Cincinnati and his past five with Cleveland.

He started 16 games at left guard for the Browns in 2010 but was cut by the Browns in March. Rookie guard Derrick Dennis was released to make room for Steinbach.

First practice

The Dolphins reported to camp Thursday and will have their first practice at 8 a.m. Friday, with 8 a.m. sessions also scheduled Saturday, Sunday and Monday.